Investigation of the low-energy kaons Investigation of the low-energy kaons hadronic interactions in light nuclei by hadronic interactions in light nuclei by AMADEUS AMADEUS K. Piscicchia* On behalf of the AMADEUS collaboration *kristian.piscicchia@lnf.infn.it MIN16 31/7 – 2/8 2016, YITP, Kyoto University
A MA D E U S p r o p o s a l A n t i k a o n Ma t t e r A t D A Φ N E : E x p e r i m e n t s w i t h U n r a v e l i n g S p e c t r o s c o p y A MA D E U S c o l l a b o r a t i o n 1 1 6 s c i e n t i s t s f r o m 1 4 C o u n t r i e s a n d 3 4 I n s t i t u t e s l n f . i n f n . i t / e s p e r i me n t i / s i d d h a r t a a n d L N F - 0 7 / 2 4 ( I R ) R e p o r t o n l n f . i n f n . i t w e b - p a g e ( L i b r a r y ) A MA D E U S s t a r t e d i n 2 0 0 5 a n d w a s p r e s e n t e d a n d d i s c u s s e d i n a l l t h e L N F S c i e n t i fj c C o mmi t t e e s EU Fundings FP7 – I3HP2: Network WP9 – LEANNIS; WP24 (SiPM JRA); WP28 (GEM JRA)
Why AMADEUS & DA F NE?
Why AMADEUS & DA F NE? DA F NE Double ring e + e - collider working in C. M. energy of f , producing 600 K + K - /s ≈ f → K + K - (BR = (49.2 ± 0.6)%) ● low momentum Kaons ≈ 127 Mev/c ● back to back K + K - topology KLOE KLOE ● 96% acceptance, ● optimized in the energy range of all charged particles involved ● good performance in detecting photons (and neutrons checked by kloNe group (M. Anelli et al., Nucl Inst. Meth. A 581, 368 (2007)))
Why AMADEUS & DA F NE? DA F NE Double ring e + e - collider working in C. M. energy of f , producing 600 K + K - /s ≈ f → K + K - (BR = (49.2 ± 0.6)%) ● low momentum Kaons ≈ 127 Mev/c ● back to back K + K - topology KLOE KLOE ● 96% acceptance, ● optimized in the energy range of all charged particles involved ● good performance in detecting photons (and neutrons checked by kloNe group (M. Anelli et al., Nucl Inst. Meth. A 581, 368 (2007)))
AMADEUS target + tracking inside KLOE spectrometer Implementation of dedicated solid targets & cryogenic gaseous targets (H, d, 3 He, 4 He) inside the KLOE DC. Nucl. Instrum. Meth. A671 (2012) 125-128 JINST 8 (2013) T05006 R&D activity is ongoing
or re-using the calorimeter only, with a new tracking detector
What to do meanwhile? K - absorption on light nuclei from the materials of the KLOE detector DC gas (90% He, 10% C 4 H 10 ) & DC wall (C + H) AT-REST (K - absorbed from atomic orbit) or IN-FLIGHT (p K ~ 100MeV) Advantage: excellent resolution .. s p L = 0.49±0.01 MeV/c in DC gas K - s m gg = 18.3±0.6 MeV/c 2 Disadvantage: K + Not dedicated target → different nuclei contamination → complex interpretation .. but → new features .. K - in flight absorption.
The scientific goal of AMADEUS Low energy QCD in strangeness sector is still waiting for experimental conclusive constrains on: 1) K-N potential → how deep can an antikaon be bound in a nucleus? - U KN strongly affects the position of the L (1405) state → we investigate it through ( S-p) 0 decay --- Y p CORRELATION - if U KN is strongly attractive then K - NN bound states should appear → we investigate through ( L / S- N) decay --- Y N CORRELATION 2) Y-N potential → extremely poor experimental information from scattering data - U Y N determines the strength of the final state YN (elastic & inelastic) scattering in nuclear environment → could be tested by Y N CORRELATION
K - - multi nucleon absorption and K - pp bound state search
S 0 p correlated production, goals of this analysis K- Absorption Kaonic Bound States • Pin down the contribution of the process: with respect to processes as: Yield Extraction and Signifjcance • Search for the formation of the ppK- and its decay in:
Absorption results ...is there room for the signal of a ppK- bound state ?
Evaluation of the signifjcance of the ppK- signal For B.E. = 45 MeV/c2, Width = 30 MeV/c2 F-test to evaluate the addition of an extra parameter to the fjt: Signifjcance of “signal” hypothesis w.r.t “Null-Hypothesis” (no bound state)
Conclusions - 2NA-QF yield - Bound state ppK- yield for B.E. 45 MeV/c2 and Width 30 MeV/c2 - the signifjcance of the ppK- signal is of 1 σ according to F-test O. Vazquez Doce et al., Physics Letters B 758 (2016) 134
K - 4 He → Λt 4NA cross section and yield
Λt available data Available data: ● in Helium : - bubble chamber experiment [M.Roosen, J.H. Wickens, Il Nuovo Cimento 66, (1981), 101] K - stopped in liquid helium, Λ dn/t search. 3 events compatible with the Λ t kinematics were found BR (K -4 He → Λt) = (3 ± 2) × 10 -4 /K stop global, no 4NA ● Solid targets - FINUDA [Phys.Lett. B669 (2008) 229] (40 events in different solid targets) ● T.Suzuki et al. Three- and four-nucleon absorption processes observed in the K −4He reaction at rest , arXiv:1009.5082v1 [nucl-ex] 26 Sep 2010 .
Λt correlation studies in 4 He from the DC gas : contributing processes single nucleon absorption (1NA) K - 4 He → Λ π 0 t res We require the mass of the triton K - 4 He → Σ 0 π 0 t res , Σ 0 → Λγ by TOF conversion on triton: K - 4 He → Σ 0 π 0 t , Σ 0 t / Λt Tritons are spectators, too low momentum: too low momentum: p t ~ Fermi momentum lower then the calorimeter threshold (p t ~ 500 MeV/c) checked by MC simulations 4NA processes – K - absorbed by the α particle: conversion is suppressed By the K - 4 He → Λt Σ 0 - t Back to back topology! K - 4 He → Σ 0 t , Σ 0 → Λγ
MC simulations: efficiency & resolution at-rest in-flight mass threshold at-rest M Λt invariant mass resolution = 2.2 MeV/c 2 averall detection + reconstruction efficiency for 4NA direct Λt production : in-flight at-rest
Preliminary Λt correlation studies in 4 He: mass, momentum and angle simulataneous fit data --- carbon data from DC wall --- 4NA K - 4 He → Λt in fmight MC --- 4NA K - 4 He → Λt at rest MC --- 4NA K - 4 He → Σ 0 t , Σ 0 → Λγ MC --- 4NA K - 4 He → Σ 0 t , Σ 0 → Λγ MC
Preliminary Λt correlation studies in 4 He: preliminary mass and angle momentum simulataneous fit parameters giving the contribution of the each process Total number of events = 136 4NA K - 4 He → Λt at rest → 1 ± 1 events data 4NA K - 4 He → Λt in fmight → 12 ± 3 events --- carbon data from DC wall --- 4NA K - 4 He → Λt in fmight MC BR (K -4 He(4NA) → Λt) < 1.3 × 10 -4 /K stop --- 4NA K - 4 He → Λt at rest MC s (100 ± 19 MeV/c) (K -4 He(4NA) →Λt) = --- 4NA K - 4 He → Σ 0 t , Σ 0 → Λγ MC = (0.42 ± 0.13(stat) +0.01 -0.02 (syst)) mb --- 4NA K - 4 He → Σ 0 t , Σ 0 → Λγ MC
K - - N single nucleon absorption processes
L (1405) case Chiral unitary models: Λ(1405) is an I = 0 quasibound state emerging from the coupling ● between the KN and the Σπ channels. Two poles in the neighborhood of the Λ(1405): t wo poles : about 1420 ; about = 1380 )MeV Phys. Lett. B 500 (2001), Phys. Rev. C 66 (2002), (Nucl. Phys. A 725(2003) 181) .. many others .. (Nucl. Phys. A881, 98 (2012)) .. others mainly coupled to KN mainly coupled to Σπ → line-shape depends on production mechanism Akaishi-Esmaili-Yamazaki phenomenological ● potential Phys. Lett. B 686 (2010) 23-28 Confirmation of single pole ansatz?
L (1405) case Chiral unitary models: Λ(1405) is an I = 0 quasibound state emerging from the coupling ● between the KN and the Σπ channels. Two poles in the neighborhood of the Λ(1405): t wo poles : about 1420 ; about = 1380 )MeV Phys. Lett. B 500 (2001), Phys. Rev. C 66 (2002), (Nucl. Phys. A 725(2003) 181) .. many others .. (Nucl. Phys. A881, 98 (2012)) .. others mainly coupled to KN mainly coupled to Σπ → line-shape depends on production mechanism Akaishi-Esmaili-Yamazaki phenomenological ● potential Phys. Lett. B 686 (2010) 23-28 Confirmation of single pole ansatz? CUT AT THE ENERGY LIMIT AT-REST ? NON RESONANT SHAPE ?
L (1405) case Phys.Rev.Lett.95:052301,2005 p p 0 resolution : s p ≈ 12 MeV/c Counts/(10MeV/c) m lim m lim At rest 12 C 12 C in at- In flight filght rest IN-FLIGHT K- 12C opens a window m S 0 p 0 (MeV/c 2 ) between 1416 MeV in-flight component and K-Nth p p 0 (MeV/c) p p 0 (MeV/c)
Complex interpretation due to K- H absorptions ongoing with the collaboration of A. Cieply (UJF, Prague) p p 0 resolution : s p ≈ 12 MeV/c Counts/(10MeV/c) m lim 12 C m lim 12 C At rest in at-rest filght In flight m S 0 p 0 (MeV/c 2 ) in-flight component p p 0 (MeV/c) p p 0 (MeV/c)
S + p - correlation → S + p - detected via: (p p 0 ) p - K - p Possibility to disentangle: Hydrogen, in-flight, at-rest, K - capture Phys. Lett. B 686 (2010) 23-28 p p - resolution : s p ≈ 1 MeV/c T otal T otal IF H H IF 12C IF 4He AR 12C AR 4He
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